A series motor has a 230 V supply and draws 108 A when running at 555 rpm. The armature resistance is 0.12 Ω and the resistance of the series field winding is 0.04 Ω. For 108 A, consider the flux per pole to be 0.022 Wb and for 46 A, consider it to be 0.017 Wb. (a)Calculate the emf generated when the current is 108 A.

(b)Knowing that E α n* Φ , calculate the new emf generated and the new speed when the motor operates at 46 A.

Afluid flows with a velocity field given by v=(x/t)i.. determine the local and convective accelerations when x=3 and t=1.

Adouble-strand no. 60 roller chain is used to transmit power between a 13-tooth driving sprocket rotating at 300 rev/min and a 52-tooth driven sprocket. a) what is the allowable horsepower of this drive? b) estimate the center-to-center distance if the chain length is 82 pitches. c) estimate the torque and bending force on the driving shaft by the chain if the actual horsepower transmitted is 30 percent less than the corrected (allowable) power.

Apipe with an outside diameter of 15 cm is exposed to an ambient air and surrounding temperature of -20°c. the pipe has an outer surface temperature of 65°c and an emissivity of 0.85. if the rate of heat loss from the pipe surface is 0.95 kw per meter of length, the external convective heat transfer coefficient (h) is: (a) 12.5 w/m"k (b) 18.6 w/mk (c) 23.7 w/mk (d) 27.9 w/mk (e) 33.5 w/mk